At the same time, the Iranian leader told Macron that statements European support “should be combined with actions and tangible measures.” Rouhani said he hopes the efforts to preserve the treaty by France, the United Kingdom, Germany, China and Russia—all signatories of the agreement—will be successful.

Macron responded to Rouhani by saying that he “hoped that Iran, for its part, will fulfill its obligations without any ambiguity,” Reuters reported. The French president also updated his Iranian counterpart on “the progress in the work being done” from Europe’s side.

President Donald Trump backed out of the 2015 agreement, considered a landmark foreign policy achievement of his predecessor, Barack Obama, on May 8. Long an opponent of the Iran nuclear accord, Trump had criticized the pact as “the worst deal ever.”

Announcing his decision, Trump said the international deal was “horrible” and “one-sided.”

“The deal allowed Iran to continue enriching uranium, and, over time, reach the brink of nuclear breakout,” the president said.

Since then, European leaders, as well as Russia and China, have expressed their commitment to move forward with the JCPOA. Leaders in France, the U.K. and Germany, traditional allies of the U.S., have expressed disappointment and criticism over Trump’s decision.

During a June 1 meeting with China’s foreign minister, the European Union’s foreign policy chief Federica Mogherini said Europe and other parties to the agreement will work “in full coordination” to ensure the pact stays in place.

The Iran agreement is just one of several major foreign policy decisions over which Trump has clashed with European leaders since he took office.

Last June, the president confirmed that he would remove the U.S. from the Paris climate agreement. The decision drew significant criticism from European leaders as well. The U.S. is now the only country in the world that is not part of the accord, after Syria joined in November.

Trump increased tensions further on May 31, when his administration imposed a 25 percent tax on imported steel and a 10 percent tax on imported aluminum. The U.S. president’s move immediately angered European leaders and other foreign trading partners.

Last Thursday, Macron expressed the level of discord between European allies and the U.S., suggesting that the G-7 nations wouldn’t “mind being six.”

“The six countries of the G-7 without the United States are a bigger market taken together than the American market,” he said. “There will be no world hegemony if we know how to organize ourselves. And we don’t want there to be one.”